Apparatus for casting.



Patented Mar. 11, 1913.

UNITED STATES PATENT oEEIoE.

FRED LLOYD MARK, CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, TO

THE RANSOM & RANDOLPH COMPANY. OF TOLEDO, OHIO, A CORPORATION OF OHIO.

APPARATUS FOR CASTING.

Specification of Letters Patent.

Patented Mar. 11, 1913.

Application filed December 23, 1907. Serial No. 407,726.

. metals is greatly facilitated.

A further object is the production of an apparatus by means of whichmetal castings, such, for instance, as those intended for fillings fordental cavities, may be quickly formed in proper condition for immediateinsertion within the cavity.

A further object is the production of an apparatus by the utilization ofwhich the castings formed will have a greater density than thoseheretofore formed by the ordinary process, and at the same time willmore accurately follow the intricate configurations of the mold.

A further object isthe utilization of a vacuum in the production ofmetallic cast- 1n i further object is the production of a device thatcan be cheaply constructed, easily operated and one that is not liable.to disarrangement of parts.

These and such other objects as may here inafter appear are attained bymy devic embodiments of which are illustrated in the accompanyingdrawings, in which the figure represents a side elevation of my device,which includes a sectional view through the center of the flask.

Like numerals of reference indicate like parts in the figure of thedrawing.

Referring now to the drawing, 3 represents a vessel air tight, with theexception of an opening 4 in which is fitted a connection 1n the form ofa cross 5. A valve 6 terminating in a nozzle 7 communicates with oneside of the cross, and a similar valve 8 isconnected with the o positeside of the cross from which exten s a tube 9 havin an upwardly turnedelbow 10. Seats upon the top of the connection or elbow 10, and in opencommunication therewith, is a circular flask support 11 the sides ofwhich taper upwardly, as clearly shown in section. Seated within thisflask sup port is a frusto-oonical flask 12, adapted to fit closelyagainst the inner periphery of the support 11. Extending upwardly fromthe top of the cross 5 is a tube 13 communicating with a vacuum gage 14;while connected to the nozzle 7 of the valve 6 is a tube 15communicating with an ordinary air pump not shown. It will thus be seenby closing the valve 8 and opening the valvefi the operation of the airpump, not shown, will create a partial vacuum within the chamber of thereceptacle 3; When this pressure has reached the desired degree, asindicated by the gage 14, the valve 'is closed. When it is desired toutilize this device in the making of small castings or inlays such asare used by dentists for filling dental cavities, the flask 12 is filledwith investment material 16, and a pattern formed from wax or somesimilar material of the exact configuration of the desired casting. Thispattern may be held in lace by a sprue former of similar material: or anordinary sprue former may be employed and removed before subjecting theflask and contents to the action of heat. The top of the investmentmaterial is hollowed out, forming a cup, which, after the removal of thesprue former, or after the absor tion of the pattern and sprue former,by eat in the. body of the investment material, is in open communicationwith the mold cavlty 18. The flask is then in condition to be placedwithin the flask holder 11, and the material from which the inlay orcasting is to be formed, and which is shown as 19, may be placed in thecup. This may be poured therein in a molten condition, or may be placedwithin the cup and melted therein by the'use of a blow pipe, or anyother similar contrivance.

As soon as the material from which the casting is to be formed is in asuitable molten condition, the valve 8 is opened, and the vacuum chamber3 put in direct communication with the interior of the flask.This-forces the molten material through the sprue channel 20 and intothe mold cavity 18. It may he often necessary when the flask is large,or conditions so demand, to place in the upper portion of the investmentmaterial a layer 21 of denser material. Of course, it is understood thatthe sprue channel passes through this material, and in this constructionthere is very little opportunity for air to be forced through the denserportion, consequently when the valve 8 is opened and the atmosphericpressure forces the gold or material from which the casting is to bemade through the "sprue channel, very little, if any, air will be forcedthrough the impervious layer, but the pressure will follow the materialdown the sprue channel and'force it into all the interstices w of themold, thus forming a dense and homogeneous casting.

It will be noted that the flask and flask holder are frusto-conical,or'slightly tapering' upwardly. I find, this quite an important feature,for by means of it the flask'is more closely fitted within" the holderand at the same time the investment material is less liable to crackaway from the inner surface ofthe flask after being subjected to theintense heat necessary to melt .out the pattern, and in melting thematerial from which the casting is to be formed. In this con-v nectionthere is considerable advantage in the factthat the flask holder andflask while rigidlysupported from thevacuum tank or reservolr are offsetso as to leave a considerable clear space around and beneath the flaskand flask holder.for the accommoda 'tion of the burner which is used toheat the flask prior to the operation of casting.

I find in practice in the manufacture of small inlays or castings that,it isunnecessary to use any layer of denser material, the investmentmaterial itself forming suflicient resistance to the introduction of theair, so that the greater force is applied on the metal through the spinechannel.

As noted above, my device is peculiarly adapted for the manufacture ofinlays for dental use, and the complete operation is as follows: Thedental cavity is first put in condition for filling in the ordinarymanner,' care being taken that'there are no reentrant cavities orrecesses formed, as it is necessary to insert the filling from without.The Wax or absorbent material from which the pattern is formed is thenforced into the cavity. The result of the pattern will, of course,conform exactly to t-heshape of the 59 cavity, and can then be lifted ordrawn'out.

After the inlay has been cast, the interior of the dental cavity iscoated with a cement and the inlay pressed in place.

It has been found that fillings so constructed and so put in place aremuch more durable than those filled by the old process.

Under the old system of forcing amalgam into a cavity, or of hammeringgold therein, air spaces are often left between the maea terial and theinner walls of the cavity, with a consequent liability to a furtherdecay of the teeth. By the use of my device, however, the fillingexactly conforms to the cavity filling and no interstices are left. So,also in the operation of filling the teeth,.

as. the casting of small articles from precious metal, and even thecastingof large articles from steel, brass, aluminum, or othermaterials. Of. course, various modifications and changes. in theapparatus and use will occur to the individual operator,-but they willall come within the limits of my invention, which is the utilization ofvacuum with the consequent atmospheric pressure in the casting of metal.

I claim:

1. In combination, a vacuum reservoir tank,and flask supporting meanscarried directly upon said tank and by the tank alone, said flasksupporting means being connected with the interior thereof by means of a,valve controlled passageway.

2. In combination, a flask, vacuum producing means connected with saidflask, a mass of porous material having a cavity therein disposed insaid flask, and a layer of material of greater density associated withsaid porous mass in position to separate the vacuum producing means fromthe atmosphere, there being a sprue through said porous mass and saiddenser layer to said cavity.

3. In combination, a mass of porous material having a cavity therein,one side of said mass being exposed, a vacuum chamber connected withtheother side ofsaid mass,

and a layerof material-of greater density associated with saidfirstnamed side of said mass to separate it from the atmosphere, therebeing'a sprue through said mass and said denser layer to said cavity.

4.- In combination, a vacuum reservoir tank, and a section of rigid piperigidly secured upon said reservoirt-ank and having an offset portionspaced from the tank, said ofi'set portion being adapted for thereception of a mold flask.

5. In combination, a vacuum reservoir, a section of rigid pipe rigidlysecured upon said reservoir tank and extending outwardly from the bodyof the tank to clear the body so as to leave a considerable clear spacebe-. low the end of the pipe, flask holding means at the end of thepipe, said pipe being adapted to pneumatically connect the interior ofsaid tank with said flask holding means and the interior of a flaskcarried thereby, and I a manually operated valve in said pipe.

6. In combination, a vacuum tank, a flask 130 containing a mass ofporous material having a mold cavity therein, the upper surface of theporous material in the flask being formed into a crucible in whichmetalmay be melted, there being a direct permanently open restrictedassageway between the bottom of said cruci 1e and said mold cavity, apipe pneumatically connecting said mass of porous material with saidtank and a valve in said passageway, the said "alve acting when closedto retain air in the space between the valve and the bottom of thecrucible whereby the flow of metal through the said restrictedpassageway is prevented until the said valve is opened.

7. In combination, a vacuum reservoir tank, a section of rigid piperigidly secured upon said reservoir tank and extending outwardlythereform to clear the body of said tank so as to leave aconsiderableclear space below the end of the pipe, a mold flask carried upon the endof the pipe, and a crucible in direct communication with the mold alsocarried by the flask.

8. In dental inlay casting apparatus, the combination of a vacuum tank,a flask su porting shelf, a narrow outer sectionvof t e shelf beingfinished to be engaged with air tight fit by the finished end of a flasksupported by the shelf, the inner section of the shelf being recessed toform a spacebelow the interior of a flask supported on thefinished'outer section of the shelf, and means for connecting said spacewith said tank.

9. In dental inlay casting apparatus, the

a combination of a'vacuum tank, a flask supporting member, said memberbeing finished to be engaged with air tight fit bya correspondinglyfinished flask supported by said member, said member being recessed toform a space below the interior of the supported flask, and means forconnecting said space with said tank.

10. In a casting a paratus, the combination of a vacuum tan a flask inwhich metal is cast, and a flask supporting member, said flask and flasksupporting member having parts finished to'form the male and female of afrusto-conical air tight fit, said flask supporting member having acavity below the interior of the flask supported thereby, and means forconnecting said cavity with said tank.

11. In a dental inlay casting apparatus, the combination of a vacuumtank, a flask supporting member, a section of said member being finishedto a conical engaging surface to e engaged with air tight fit by acorrespondingly finished sect-ion of a flask supported by said member,the member being recessed to form a space below the interior of a flasksu ported on the finished section of said mem er, and means forconnecting 7 wardly therefrom to clear the body 0 said J tank so as toleave a considerable clear space below the end of the standard, and moldflask holding means on the end of said standard, said flask holdingmeans being pneumatically connected wlthsaid tank.

13. In combination, a vacuum tank, a flask containing a mass of porousmaterial having a mold cavity therein, a crucible in which metalismelted on top of said material, there being a direct permanently openrestricted passageway between the bottom of said crucible and saidcavity, a pipe pneumatically connecting said mass wlth said tank, avalve in said passageway, and a vacuum gage in open communication withsaid tank.

Signed by me at Chicago, Illinois, this 14th day of December, 1907. v

a F. LLOYD MARK. WVitnesses ALBERT J 01 m SAUsnR, SARAH LEWIS.

